Spark-plug



G. L-. BREWER.

SPARK PLUG. APPLICATION FILED OCT. 14, 1919.

Patented Feb. 22, 1921.

FID E GOVERNOR L. BREWER, 0F KENT CITY, MIGHIGAN.

SPARK-PLUG.

Specification of Letters Patent. Patnted F b 22 1921 Application filed October 14, 1919. Serial No. 330,576.

To all whom it may concern.

Be it known thatI, GOVERNOR L. BREWER, a citizen of the United States, residing at Kent City, in the county of Kent and State of Michigan, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification.

This invention relates to spark plugs for igniting the combustible charges of internal combustion engines; and it consists in the novel construction and combination of the parts hereinafter fully described and claimed.

In the drawings, Figure 1 is a side view of a spark plug constructed according to this invention. Fig. 2 is a vertical section of the same. Fig. 3 is an end view. Fig. 4 is a detail sectional view showing the way the spark ring is secured to the plug. All

the views are drawn to an enlarged size, for

clearness.

The plug or plug body 2 is formed of metal, and it has a screwthreaded portion 3 for connecting it to the engine cylinder in the usual way. A tubular sleeve 4 is inserted in the plug, and is formed of porcelain or other suitable insulating material. This sleeve has a stop shoulder 5 at its middle part which bears against a corresponding' shoulder on the plug. It also has a shoulder 6 at its upper part which comes flush with the outer end of the plug, and an extension 7 which projects beyond the end of the plug.

A chamber 8 is formed atthe inner end of the plug sleeve which does not extend to the end of the plug, and a spark ring 9 is secured in this chamber. The ring is arranged flush with the inner end of the plug, and it bears against the inner end of the sleeve. The ring is secured to the plug in the said chamber by crimping or riveting over the end portion of the plug so as to retain the ring. Fig. 4 shows how the parts are made before being secured together, but the parts may be formed in other approved ways.

This spark ring has an inwardly projectlng 11p 10 at its exposed end, and holes 12 are formed in it which connect with the chamber 8 and permit the escape of air and gas from the said chamber. A rod 14 is secured in the sleeve 4, and its inner end projects flush with the exposed end of the spark ring so that a spark gap is formed between them.

The outer end portion of the rod 14 is screwthreaded at 15, and projects from the outer end of the plug, and 17 is a collar of insulating material which is slipped over the part 15 and which has a recess 18 which is slipped over the extension 7 on the sleeve, so that the collar bears againstthe end of the plug, and insulates it from the rod. A' nut 19 is screwed on the rod for securing it in the sleeve, and 20 is a thumb-nut on the rod for clamping the line wire to it in the usual manner.

The rod 14 and the sleeve 4 are put in" place from the lower end of the plug, and the rod is prevented from sliding upwardly by a shoulder25 at its lower part or by making it to fittightly in the sleeve, and the sleeve is held in its place by the spark ring 9 and the lip 26 riveted around the edge of the spark ring at the inner end of the plug 2.

What I claim is:

In a spark plug, a plug, a sleeve of insulating material secured in the plug and forming a chamber at its inner end portion, a spark ring having a main portion of the same thickness as the depth of the said chamber and secured in it with its inner end bearing against the end of the said sleeve and with 1ts outer end flush with the end of the plug, said main portion having an inwardly-projecting annular lip at its outer end, and a rod secured in the said sleeve and projecting through the spark ring and forming a spark gap with the said inwardly-projecting lip.

In testimony whereof I have afiixed my signature.

. GOVERNOR L. BREWER. 

